From patchwork Wed Aug 8 22:16:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zanoni, Paulo R" X-Patchwork-Id: 10560527 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DB8021390 for ; Wed, 8 Aug 2018 22:16:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CF1082AF13 for ; Wed, 8 Aug 2018 22:16:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C35122B05E; Wed, 8 Aug 2018 22:16:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 863FB2AF13 for ; Wed, 8 Aug 2018 22:16:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 364B76E5F8; Wed, 8 Aug 2018 22:16:27 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id B7D8E6E5F5 for ; Wed, 8 Aug 2018 22:16:25 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2018 15:16:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,212,1531810800"; d="scan'208";a="73856687" Received: from przanoni-mobl.jf.intel.com ([10.24.10.250]) by orsmga003.jf.intel.com with ESMTP; 08 Aug 2018 15:16:16 -0700 From: Paulo Zanoni To: intel-gfx@lists.freedesktop.org Date: Wed, 8 Aug 2018 15:16:12 -0700 Message-Id: <20180808221614.15486-2-paulo.r.zanoni@intel.com> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180808221614.15486-1-paulo.r.zanoni@intel.com> References: <20180808221614.15486-1-paulo.r.zanoni@intel.com> Subject: [Intel-gfx] [PATCH 2/4] drm/i915: BUG() if we can't lookup_power_well() X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paulo Zanoni MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP None of the current lookup_power_well() callers are actually checking for NULL return values, they all just use the pointer right away. Replacing these theoretical segfaults with BUG()s at least makes our code a little more explicit to the reader. We can only hit this NULL/BUG() condition if we try to lookup a power well that isn't defined on a given platform. If that ever happens, we have to fix our code, making it lookup the correct power well. Because of this, I don't think it's worth trying to implement error checking in every caller. Improving our CI system will be a better use of our time once a bug is found in the wild. Cc: Imre Deak Signed-off-by: Paulo Zanoni --- drivers/gpu/drm/i915/intel_runtime_pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index e0947f662361..2fdb1f4125c2 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -1120,7 +1120,8 @@ lookup_power_well(struct drm_i915_private *dev_priv, return power_well; } - return NULL; + /* Tried to lookup a power well that doesn't exist for the platform. */ + BUG(); } #define BITS_SET(val, bits) (((val) & (bits)) == (bits))